Novel cyanine dyes containing a 1-oxy-3,4-dioxocyclopentene-1 ring in the conjugated methine chain linking two nitrogen containing heterocyclic nuclei

ABSTRACT

A CYANINE DYE HAVING ONE OF THE FORMULAE:   1-((+)M-O-),2-(R1-N-C(-Z1)=CH-),3,4-DI(O=),5-(R2-N(+)-C   (-Z2)-CH=)CYCLOPENT-1-ENE X(-) AND   1-((-)O-),2-(R1-N-C(-Z1)=CH-),3,4-DI(O=),5-(R2-N(+)-C(-Z2)   -CH=)CYCLOPENT-1-ENE   WHEREIN: EACH OF R1 AND R2 IS SELECTED FROM THE CLASS CONSISTING OF LOWER ALKYL, ALLYL, ARALKYL, AND ARYL, EACH OF Z1 AND Z2 REPRESENTS THE ATOMS NECESSARY TO COMPLETE A HETEROCYCLIC NUCLEUS, X- IS AN ANION BUT IS NOT PRESENT WHEN R1 AND/OR R2 CONTAINS AN ANIONIC GROUP, AND M+ IS A CATION, IS DESCRIBED. THESE DYES ARE USEFUL OPTICAL SENSITIZING AGENTS FOR THE SENSITIZATION OF LIGHT-SENSITIVE ELEMENTS.

United States Patent M NOVEL CYANINE DYES CONTAINING A l-OXY- 3,4DIOXOCYCLOPENTENE-l RING IN THE CONJUGATED METHINE CHAIN LINKING TWONITROGEN CONTAINING HETEROCYCLIC NUCLEI Guy Alfred Rillaers, Kontich,and Henri Depoorter, Mortsel, Belgium, assignors to Agfa-Gevaert N.V.,Mortsel, Belgium No Drawing. Original application June 17, 1969, Ser.No. 834,169, now Patent No. 3,615,417, dated Oct. 26, 1971. Divided andthis application Mar. 4, 1971, Ser.

Int. Cl. C09b 23/00 U.S. Cl. 260-240 R 8 Claims ABSTRACT OF THEDISCLOSURE A cyanine dye having one of the formulae:

X. t j 1* R; g R;

and

o- Z1\ Z2 /C=CH CH-C r R1 I (L Ra wherein:

each of R and R is selected from the class consisting of lower alkyl,allyl, aralkyl, and aryl,

each of Z, and Z represents the atoms necessary to complete aheterocyclic nucleus,

X is an anion but is not present when R and/ or R con tains an anionicgroup, and

M+ is a cation,

is described. These dyes are useful optical sensitizing agents for thesensitization of light-sensitive elements.

This application is a division of U.S. Ser. No. 834,169 filed June 17,1969, now U.S. Pat. No. 3,615,417 granted Oct. 26, 1971.

The present invention relates to new methine dyes, to the preparationthereof, to their use as optical sensitizing agents for thesensitization of light-sensitive elements, more particularlylight-sensitive silver halide and photoconductive compounds, and tolight-sensitive elements sensitized therewith.

Numerous methine dyes and their use as spectral sensitizers inphotographic light-sensitive silver halide elements have been described.However, among these sensitizers only a few are suitable for extendingthe sensitivity of photographic silver halide emulsions to the extremered region beyond 700 nm. of the spectrum. Moreover, the sensitizingaction of the known far-redsensitizers and their poor stability (keepingpower) often make them unsuitable for practical use.

Spectral sensitization of photoconductive inorganic substances such aszinc oxide can also be performed with methine dyes as described e.g. inUnited States patent specification 3,128,179. The dyes proposed for thespectral sensitization of photoconductive inorganic compounds have asensitizing action only for a well defined part of the visible spectrum.Moreover, these spectral sensitizers having their main absorption in thevisible region of the 3,793,313 Patented Feb. 19, 1974 ICC spectrum,strongly dye the photoconductive layer when used in the required amountand therefore necessitate, as described in United Kingdom patentspecification 1,020,- 755 the use of additional dyes compensating theundesirable coloring of the photoconductive layer. In practice, amixture of at least twomost often more than twodyes must be used forobtaining a high sensitivity when exposing a photoconductive layer to anilluminating source such as an ordinary light bulb and/or for obtaininga neutral tint of the photoconductive layer.

Therefore, it is an object of the present invention to provide a classof new stable spectral sensitizing agents for inorganic photoconductivesubstances such as photoconductive zinc oxide and for light-sensitivesilver halide,

which have favourable spectral sensitizing effects and do not have thementioned disadvantages.

In accordance with the present invention new cyanine dyes are providedwhich are characterized in that the conjugated methine chain linking thetwo nitrogen containing heterocyclic nuclei contains a1-oxy-3,4-dioxocyclopentene-l ring.

Particularly suitable sensitizing dyes according to the presentinvention are the dyes corresponding to the following general formulae:

Each of R and R (the same or different) stands for a substituent of thetype contained in cyanine dyes on the cyanine nitrogen atom, e.g. analkyl group such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, asubstituted alkyl group such as fi-hydroxyethyl, fl-acetoxyethyl,carboxymethyl and carboxyethyl as described in the German patentspecification 704,141, sulphoalkyl as described in the United Kingdompatent specification 742,- 112 such as sulphoethyl, sulphopropyl,sulphobutyl, sulphatoalkyl as described in the French patentspecification 1,149,769 such as sulphatopropyl and sulphatobutyl, thegroup -A-W-NH-V-B wherein A, W, V and B have the same significance asset forth in United Kingdom patent specification 904,332 such as aN-(methylsulphonyl)- carbamyl-methyl group, -(acetylsulphamyl)-propyl, a5 (acetylsulphamyl) butyl group, an allyl group, an aralkyl group e.g. abenzyl group, a substituted aralkyl group such as carboxybenzyl andsulphobenzyl, an aryl group such as phenyl, a substituted aryl groupsuch as carboxyphenyl, or a cycloalkyl group such as cyclohexyl.

Each of Z and Z (the same or different) represents the non-metallicatoms necessary to complete a heterocyclic nucleus containing 5 or 6atoms in the heterocyclic ring e.g. a nucleus of the thiazole series(e.g. thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole,4-(2-thienyl)-thiazole), those of the benzothiazole series (e.g.benzothiazole, S-chlorobenzothiazole, S-methylbenzothiazole,6-methylbenzothiazole, 5,6-dimethylbenzothiazole, S-bromobenzothiazole,5-phenylbenzothiazole, 5-

methoxybenzothiazole, 6-methoxybenzothiazole,5,6-dimethoxybenzothiazole, 5,fi-dioxymethylenebenzothiazole,S-hydroxybenzothiazole, 6-hydroxybenzothiazole, 4,5,6,7-tetrahydrobenzothiazole, those of the naphthothiazole series (e.g.naphtho[2,1-d]thiazole, naphtho[1,2-d]thiazole, S-methoxynaphtho 1,2-d]thiazole, S-ethoxynaphtho [1,2-d] thiazole,8-methoxynaphtho[2,1-d1thiazole, 7-methoxynaphtho[2,1-d]thiazole), thoseof the thionaphtheno [7,6-d]thiazole series (e.g.7-methoxythionaphtheno[7,6- d]thiazole), those of the oxazole series(e.g. 4-methyloxazole, S-methyloxazole, 4-phenyloxazole,4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole,S-phenyloxazole), those of the benzoxazole series (e.g. benzoxazole,S-chlorobenzoxazole, S-methylbenzoxazole, 5- phenylbenzoxazole,6-methylbenzoxazole, 5,6-dimethylbenzoxazole, S-methoxybenzoxazole,6-meth0xybenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole), thoseof the naphthoxazole series (e.g. naphtho[2,1-d] oxazole,naphtho[1,2-d]oxazo1e), those of the selenazole series (e.g.4-methy1selenazole, 4-pheny1selenazole), those of the benzoselenazoleseries (e.g. benzoselenazole, 5- chlorobenzoselenazole,S-methylbenzoselenazole, 5,6-dimethylbenzoselenazole, 5methoxybenzoselenazole, 5- methyl-6-methoxybenzoselenazole, 5,6dioxymethylenebenzoselenazole, S-hydroxybenzoselenazole,4,5,6,7-tetrahydrobenzoselenazole), those of the naphthoselenazoleseries (e.g. naphtho[2,1-d]selenazole, naphtho[1,2-d] selenazole), thoseof the thiazoline series (e.g. thiazoline, 4-methylthiazoline,4-hydroxymethyl-4-methylthiazoline, 4,4-bis-hydroxymethylthiazoline),those of the oxazoline series (e.g. oxazoline), those of theselenazoline series (e.g. selenazoline), those of the 2-quinoline series(e.g. quinoline, 6.methylquinoline, 6-chloroquinoline,6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline), those of the4-quinoline series (e.g. quinoline, 6-meth0xyquinoline,7-methylquino1ine, 8-methylquinoline), those of the l-isoquinolineseries (e.g. isoquinoline, 3,4-dihydroisoquinoline), those of the3-isoquinoline series (e.g. isoquinoline), those of the3,3-dialkylindolenine series (e.g. 3,3-dimethylindolenine,3,3-dimethyl-S-chloroindolinine, 3,3,5-trimethylindolenine,3,3,7-trimethylindolenine), those of the pyridine series (e.g. pyridine,S-methyl pyridine), or those of the benzimidazole series (e.g. l-ethyl-5,6 dichlorobenzimidazole, 1-hydroxyethyl-5,6-dichlorobenzimidazole,1-ethyl-S-chlorobenzirnidazole, 1-ethy1-5,6- dibromobenzimidazole,1-ethyl-5-phenylbenzimidazole, 1- ethyl-S-fluorobenzimidazole, 1ethyl-S-cyanobenzimidazole, I-(B-acetoxyethyl)-5-cyanobenzimidazole,l-ethyl-S- chloro-G-cyano benzimidazole, l-ethyl-S-fluoro--cyanobenzimidazole, l-ethyl-S-acetylbenzimidazole, 1-ethyl-5-carboxybenzimidazole, l-ethyl-S-ethoxycarbonylbenzimidazole,1-ethyl-5-sulphamylbenzimidazole, 1- ethyl-S-N-ethylsulphamylbenzimidazole, 1 ethyl-5,6-difluorobenzimidazole,1-ethyl-5,6-dicyanobenzimidazo1e, l-ethyl-S-ethylsulphonylbenzimidazole, 1-ethyl-S-methylsulphonylbenzimidazole,1-ethyl-5-trifiuoromethylbenzimidazole,lethyl-5-tri.fluoromethylsulphonyl-benzimidazole, l-ethyl-S-trifluoromethylsulphinylbenzimidazole, and

X- represents an anion such as a chloride ion, a bromide ion, an iodideion, a perchlorate ion, a benzene sulphonate ion, a p-toluenesulphonateion, a methylsulphate ion, an ethylsulphate ion, a propylsulphate ion,but X- is not present when R and/or R itself contains an anionic group,e.g.

M+ stands for a cation e.g. a hydrogen cation, a metal cation or anonium cation of inorganic or organic nature such as ammonium andpyridinium.

The following is a non-limitative list of representative examples ofcyanine dyes according to the present invention. For the sake ofconvenience the dyes are represented in the form of their betainestructure although in the S S T ll H3 "'N I "kl aHs 2B:

- S e n N .l 7): I Da SOaH.C5H5N S:H.C5H5N As will be illustratedhereinafter by the preparations the new cyanine dyes according to thepresent invention can be prepared by condensation of croconic acid orderivatives thereof such as monoand dialkyl esters thereof with aZ-methyl-cycloamrnonium quaternary salt known in cyanine dye chemistryor with the corresponding Z-methylene base. The condensation reaction iscarried out in the presence of a diluent e.g. methanol, acetonitrile,dimethyl sulphoxide, tetrahydrothiophene-l,l-dioxide, nitromethane,dimethylformamide, etc. and/ or in the presence of a basic condensingagent e.g. a trialkyl amine such as triethyl amine, a dialkyl aniline, aheterocyclic tertiary amine such as pyridine or N-alkylpiperidine or thelike.

PREPARATION lzDYESTUFF 4 To a solution of 2.85 g. ofanhydro-2,5-dirnethyl-3-(3- sulphopropyl)benzothiazolium hydroxide and0.90 g. of croconic acid (prepared according to the method of Eistert etal., Ber. 93,1464) in 10 ml. of methanol, 7 ml. of pyridine are added.The solution is heated for about 20 min. on a warm water bath whereuponit is cooled and left standing for some time in the refrigerator. Thebronze coloured dye formed is filtered 011 and washed with cold methanoluntil the washings are no longer magenta coloured. Finally the dye iswashed with some ether and dried. Yield: 1.7 g. (41% The dye issparingly soluble in methanol, but shows a good solubility in water anddimethyl sulphoxide. It exhibits a strong solvatochromism. As a matterof fact its absorption maximum lies at 680 nm. when measured in waterand at 800 nm. when measured in dimethyl sulphoxide.

The dyes 2, 3, 5 and 7 of the above list can be prepared in a similarway as dye 4.

PREPARATION 2: DYESTUFF l 1.20 of Z-methyl-3-ethyl-benzothiazoliumiodide and 0.30 g. of croconic acid are taken up in 20 ml. of pyridinewhereupon 0.6 ml. of triethylamine is added whereby the reactantsdissolve. The solution is left standing overnight at room temperaturewhereupon the pyridine is partially removed by evaporation under reducedpressure and the residue is cooled in order to complete crystallization.The bronze-colored dye is washed twice with methanol and dried. Yield:0.5 g. (54% Dye 6 of the above list of dyes can be prepared in a similarway.

PREPARATION 3: DYESTUFF 10 A5" solution is prepared of 5.20 g. .of2,3-dimethylnaphtho[1,2-d]thiazoliurn methyl sulphate and 1.12 g. ofcroconic acid in a mixture of 25 ml. of methanol and 25 ml. of pyridine.To this solution 4 ml. of triethylamine are added whereupon the solutionis boiled for 10 min. on a warm water bath. The dye crystallized uponcooling, is filtered off and washed with methanol and ether. Yield: 0.5g. (12%).

The dyes 8 and 12 of the above list of dyes can be prepared in a similarway.

6 PREPARATION 4; DYESTUFF 9 1.35 g. of1,2,3,3-tetramethyl-5-chloro-indoleninium iodide and 0.43 g. of croconicacid dimethyl acetal (prepared as described by Malachowski andPrebendowski in Ber. 71, 2241) are dissolved in 12 ml. of pyridine. Themixture is left standing for several hours at room temperature and thenheated for a few minutes on a boiling water bath. The dye isprecipitated with ether and purified by washing with a little water andwith ether. Yield: 0.08 g. (8%

PREPARATION 5 DYESTUFF 11 To 3.17 g. of2,5-dimethyl-3-ethylbenzothiazolium methyl sulphate in 7 m1. ofmethanol, 0.8 g. of croconic acid dissolved in a mixture of 5 ml. ofpyridine, 3 ml. of methanol and 1 ml. of triethylamine is added. Afterhaving been kept 3 days at room temperature the dye is collected bysuction and washed with ethanol until the washings are no longer magentacolored. Yield: 1.4 g. (29% 1 Measured in dimethylsulphoxide unlessotherwise stated. 9 Measured 1n methanol. Measured in metacresol.

The novel cyanine dyes according to the present invention are useful forspectrally sensitizing inorganic photoconductive compounds e.g.photoconductive zinc oxide dispersed in a binder.

A photoconductive zinc oxide layer when sensitized by means of a dyeaccording to the present invention possesses a uniform sensitivity inthe visible region of the spectrum and a high general sensitivity whenexposed to an ordinary light bulb. Therefore, in accordance with thepresent invention it sufiices to add one single sensitizer to thephotoconductive zinc oxide composition in order to obtain the desiredsensitivity where otherwise two or more spectral sensitizers arerequired to obtain the same effect.

A part from having a favorable sensitizing action on photoconductivezinc oxide the dyes according to the present invention confer only avery low and neutral coloring to the photoconductive layer owing to thefact that the main absorption maximum of the dyes is situated beyond 700nm., i.e. beyond the visible region of the spectrum. Thus, in accordancewith the present invention there can be dispensed with the use ofcompensating dyes as described above.

The sensitizing dyes used in the present invention can be allowed toabsorb to the inorganic photoconductive substance, preferablyphotoconductive zinc oxide, by adding them to a dispersion of thatsubstance in an organic or aqueous medium either or not alreadycontaining the binder.

Zinc oxide recording layers applied from organic solvents and bindingagents soluble in the organic medium are described e.g., in the Belgianpatent specification 612,102 and in the French patent specification1,560,975.

Zinc oxide recording layers applied from an aqueous medium are describedin the United Kingdom patent specifications 1,125,579 and 1,125,580.

The spectral sensitizing agents are preferably added in dissolved state,e.g. dissolved in a water-miscible solvent or in water, to a dispersionof the photoconductive zinc oxide. When applied in an aqueous zincoxide'dispersion they are preferably incorporated into the recordinglayer from an organic liquid consisting of or containing av solvent,which has a very low vapor pressure and which is at least for 20% byweight soluble in water at 20 C. Such a method for sensitizing aphotoconductive material is described in the French patent specification1,517,558, which specification should be read in conjunction herewith.

Suitable dispersing agents for dispersing photoconductive zinc oxide inan aqueous medium are described in the French patent specification1,540,020, which specification should also be read in conjunctionherewith.

The optimum quantity of sensitizing agent per gram of photoconductivezinc oxide can be determined easily by a series of tests. A useful rangeis comprised between 0.01 mg. and 2 mg. per gram of photoconductive zincoxide. The weight ratio of zinc oxide to binder may vary betweenrelatively large limits. A ratio of 1 part by weight of photoconductivesubstance to 0.1 to 0.6 part by weight of total content of binder ispreferred. Advantageously the coating mixture contains dispersedphotoconductive zinc oxide in a weight ratio of 95% to 60% in respect ofthe total solids content of the coated and dried layer. The thickness ofthe photoconductive layer may be chosen between wide limits according tothe requirements of each case. Good recording and reproduction resultsare attained with electrophotographic layers having a thickness of 1 to20 and preferably of 3 to Preferably the sensitizing substances are usedin combination with photoconductive zinc oxide prepared according to theFrench process.

The photoconductive recording layers containing a spectral sensitizingagent as above described may contain, in addition to the photoconductivesubstance(s) and the binder, spectral sensitizers of any other type (seee.g. United Kingdom patent specification 1,020,504), compoundsincreasing the dark-resistivity, e.g. the phosphorus compounds describedin the Belgian patent specification 612,102, and additives known incoating techniques e.g. pigments (see e.g. United Kingdom patentspecification 1,007,349), compounds influencing the gloss and/or theviscosity, and compounds that counteract aging and/or oxidation of thelayers, or which influence the thermal stability of the layers. Whenselecting any additives, preference is given to those which least reducethe dark-resistivity of the photoconductive layer.

The photoconductive composition sensitized according to the presentinvention may be coated on a support according to a known coatingtechnique, e.g. by spraying, whirling, dip-coating, or by a coatingtechnique wherein use is made of a doctor blade. The supports or basematerials are chosen in view of the particular charging, exposure,recording, development and/or transfer technique wherein the recordingmaterial is used.

In electrophotographic recording techniques, wherein Kingdom patentspecifications 995,491, 1,020,503 and- 1,020,504 and in the UnitedStates patent specification 3,008,025.

The photoconductive layer of an electrophotographic material, which isprepared starting from a coating composition according to the presentinvention, can be used for recording purposes, in which prior toexposure an electric charge is non-difl'erentially applied according toknown methods. However, the material can also be used in recordingtechniques, in which the exposure step precedes the charging step. Forsuch a technique we may refer to e.g. the United Kingdom patentspecifications 1,033,419 and 1,033,420.

For comparison of the sensitivitiy of photoconductive recordingelements, said elements are exposed in thesame manner, e.g. through astep-wedge, and developed in the same conditions. Well establishedmethods of developing electrostatic images include cascade-, powdercloud-, magnetic brushand fur brush-development. These methods are basedon the application of charged dry toner to the surface bearing theelectrostatic image. Other methods are based on the use of liquids,either insulating (electrophoretic development) or conductive liquids(see eig. the United States patent specification 2,907,674 and theBelgian patent specifications 610,060 and 625,335). Development of aconductivity image based on electrolysis is described e.g. by I. A.Amick, RCA Rev., 20, 753 (1959).

Apart from being useful spectral sensitizers for photoconductive zincoxide the cyanine dyesaccording to the present invention-also confer ahigh sensitivity for the 700-900 nm. region of the spectrum to silverhalide photographic emulsions, especially the customarily employedgelatino silver chloride, gelatino silver chlorobromide, gelatino silverbromide, gelatino silver bromo-iodide and gelatino silverchlorobromo-iodide emulsions. Photographic silver halide emulsionscontaining water-permeable colloids other than gelatin, such asagar-agar, zein, collodion, water-soluble cellulose derivatives,poly(vinyl alcohol) or other hydrophilic synthetic or natural resins orpolymeric compounds, can, however, also be sensitized with the methinedyes according to the present invention.

In order to prepare photographic emulsions sensitized according to thisinvention by one or more of the cyanine dyes, the cyanine dyes areincoporated in the photographic emulsion by one of the methodscustomarily employed in the art. In practice, it is convenient to addthe dyes to the emulsion in the form of a solution in an appropriatesolvent. The cyanine dyes can be added at any stage of the preparationof the emulsion and should be uniformly distributed throughout theemulsion. The concentration of the dyes in the emulsion may vary widely,for example from 0.1 to 30 mg. per mole of silver halide and will varyaccording to the eflect desired. The suitable and most economicalconcentration for any particular emulsion will be apparent to thoseskilled in the art, upon making the ordinary tests and observationscustomarily used in the art of emulsion making.

The cyanine dyes can be incorporated into photographic emulsions thegeneral sensitivity of which has been increased by physical and chemicalripening. As suitable chemical sensitizers may be mentioned thewell-known sulphur sensitizers such as allyl isothiocyanate,allylthiourea, sodium thiosulphate, potassium selenocyanide, the

natural sensitizers originating in the gelatin, the reducing sensitizerssuch as imino-amino-methane sulphinic acid and the derivatives thereof,cadmium salts, and the salts of noble metals such as gold, platinum andpalladium.

In preparing the photographic emulsions according to the invention, theusual addenda such as anti-fogging agents, stabilizers, antibronzingagents, hardeners, wetting agents, plasticizers, developmentaccelerators, color couplers, fluorescent brighteners and ultra-violetscreening compounds can moreover be incorporated in the emulsion in themanner customarily employed in the art.

Emulsions sensitized with the methine dyes can be coated in the usualmanner on a support such as glass, cellulose derivative film, resin filmor paper.

The following examples are to illustrate the spectral sensitizationresults obtained with methine dyes according to the present invention.

EXAMPLE 1 A series of photoconductive compositions were prepared asfollows:

.. .20 g. of photoconductive zinc oxide, 25 cos. of water ('vinylacetate/crotonic acid) (94.4/5.6) and 1.25 cc. of

Cassurit MLP (partially etherified melamine-formaldehyde resin marketedas a 80% aqueous solution by Cassella Farbwerke Mainkur A.G., Frankfurta/Main, W.

10 To these emulsions were added per mole of silver halide 3 mg. ofdyestufi' from a solution or dispersion as indicated in the table.

After a digestion time of 2 hours at 38 C. the emuly) in of Water and 1f a concentrated 5 sions were coated on a common support and dried. q FPammfmla sollltloll ?Y l- The The emulsion layers were exposed in asensitometer positions obtained were eachsensit zed by means of one h ha step wedge with constant 0.15, once without of the sensitizing agentsmentioned 1n the following table. filter (total Speed) and once througha filter (IR speed), Each sensltlllPg added In an amount of 1 5' thetransmission of which for light of a wavelength shorter PF gram of Zlncf the 9"? of soluflon m than 732 nm. is less than 0.1%, for light of awavelength gig fig i ig gs g gi an was mtlmate y mlxed wlth the longerthan 800 nm. is more than 80% and for light The sensitized compositionswere coated at a rate of g g igfifg i g fi igsl g f 3 i g f f g. of zincoxide per sq. m. on baryta coated paper supb 1 1 F lste m e ta 1e Portsweighing 90 gJsq. 15 e (3w as e num er 0 measura e steps of the wedgeAfter having been dried, the layers obtained were use 0 charged, exposedfor 15 sec. with an irradiation intensity The l f l f exPosed m aSpectrograph and of 2280 lux by means of an incandescent lamp of 450 thesensltlllng maxlma Observed a e also listed in the watt through a stepwedge having a constant 0.1. table below.

Test D e Emulsion Speed Sens. number s zfl Solution or dispersion A BTotal LR. F0

0A X 1&5 0.10 on X 16 0.15

1 100mg. per litre methanol/metacresol (9/1). g g 2% 2 100 mg. perlitremethanol/metraeresol(8/2) i: 2 3 Dispersion "Bi 1 S3 g-fg 4 mg. perlitre methanollwater(5/5) g 4 100mg. per litre dimethyliormamide {X3i--- S1! 6 100mg. per litre methanollmetacresol(1/9). 3- 2 -2 7Dispersion "gi g 3 8 8' 8A -V X 14.5 35 830 0.08 SE 10 1 x 16 15 8300.15

1 The dispersion is made by mixing for 8 hours in a swinging mill 200mg. of the dyestufi with 200 ml. of 2% aqueous gelatin in the presenceof 100 mg. of sodium oleyl methyl taurine.

TABLE Number of non-blackened steps 12 25 23 19 17 Dyestutf:

\l-bwNi l EXAMPLE 2 The following two types of emulsions A and B werespectrally sensitized by means of the dyestuifs listed in the tablebelow:

Emulsion type A: An acid gelatino silver halide emulsion, digested inthe presence of a gold compound containing 72.5 mole percent of silverbromide, 27 mole percent of silver chloride and 0.5 mole percent ofsilver iodide and comprising per kg. 0.45 mole of silver halide.

Emulsion type B: An ammoniacal gelatino silver halide emulsioncontaining 97 mole percent of silver bromide and 3 mole percent ofsilver iodide and comprising per kg. 0.33 mole of silver halide.

EXAMPLE 3 An emulsion of type B of Example 2 was spectrally sensitizedby means of the dyestuifs listed in the table below and further treatedas described in Example 2.

The following results were attained.

11 wherein: each of R1 and R is a member selected from the groupconsisting of lower alkyl, B-hydroxy lower alkyl, B-acetoxy lower alkyl,carboxy lower alkyl, sulphosubstituted lower alkyl, sulphate-substitutedlower alkyl, N-(methylsulphonyl)-carbamyl lower alkyl, acetylsulphamyllower alkyl, allyl, benzyl, carboxybenzyl, sulphobenzyl, phenyl,carboxyphenyl, and cyclohexyl, each of Z, and Z represents the atomsnecessary to complete a heterocyclic nucleus selected from the groupconsisting of thiazole nuclei, benzothiazole nuclei, naphthothiazolenuclei, ,thionaphtheno[7,6-d]thiazole nuclei, oxazole nuclei,benzoxazole nuclei, naphthoxazole nuclei, selenazole nuclei,benzoselenazole nuclei, naphtho selenazole nuclei, thiazoline nuclei,oxazoline nuclei,

, selenazoline nuclei, Z-quinoline nuclei, l-isoguinoline nuclei,3-isoquinoline 7 nuclei, 3,3-dialkyliiidolenine nuclei, pyridine nuclei,and benzimidazole nuclei, X" represents a member selected from the groupconsisting of a chloride ion, a bromide ion, an iodide ion,

a perchlorate ion, a benzene sulphonate ion, a p toluenesulphonate ion,a methylsulphate ion, an ethylsulphate ion, and a propylsulphate ion,but X- is not present when at least one of R and R itself contains ananionic group,

M+ represents a member selected from the group consisting of a hydrogencation, a metal cation, an onium cation, or a pyridinium cation. 2. Acyanine dye according to claim 1 having the formula:

3. A cyanine dye according to claim 1 having the 40 formula:

4. A cyanine dye according to claim-1 having the '50 12 A yanine dyeaccording to claim 1 having the -formula:-

formula:

7. A cyanine dye according to claim 1 having the 8. A cyanine dyeaccording to claim 1 having the formula:

References Cited:

V V p H UNIT STATES PATENTS 3,164,586 v1/1965 Ficken 26o 24 o.13,525,742 8 /l970 .Oliver 2 60*T24O.4 3,592,657 7/1971 Kampfer' 26 o-240 Rx 3, 17,270

11/1971v Kampfer 260-- 24j01;x

OTHER REFERENCES Hamer: The Cyanine Dyesqand Related Compounds,

pp. 270- -27l and 277, Interscience Publishers (1964.), v: JOHNRANDOLPH, Primary Examiner us. c X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 79s,31s Dated February 19, 1974 Inventor(s) Guy Alfred RILLAERS ET AL It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 1, in the heading, insert the claim for priority as follows:

Priority is claimed of- Great Britain No. 32, 351/68 filed July 5, 1968Column 6, line 61, "absorb should read adsorb Column 7, line 63, "3,008, 025" should read 3, 008, 825 Column 9, line 46, "players" shouldread layers Column 10, in the table, under the heading "Dyestuff, "4"(second occurrence) should read 5 Column 10,

in the table, under the heading "Test number, immediately followingnumbers "8A and 8B" delete "10" (first occurrence). Column 12, lines 1621, claim 6, the formula shguld appear as follows:

l CH, t5 :5 a

Signed and sealed this 22nd day of October .1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner. ofPatents F ORM PO-I 050 (10-69) USCOMM-DC 60376-P69 1? U.S. GOVERNMENTPRINTING OFFICE I!!! 0-36-534.

